Boil 150 ml water with 150 g sugar for 2 minutes, add juice from 0.5 lemon, and set aside to cool.
In a bowl, mix 150 ml yogurt, 150 g sugar, and 1 packet vanilla sugar until combined. Mix in half of the melted butter, 150 g semolina, 50 g blanched almonds, and 1 teaspoon baking powder.
Grease a rectangular mold with fat and pour the batter to about 3 cm height.
Bake in a preheated oven at 180°C (356°F) with top and bottom heat for 30 minutes.
Remove from oven and pour the syrup evenly over the basbousa. Cut into squares or diamonds and return to oven at 180°C (356°F) for 3 minutes.
Remove from oven, pour remaining melted butter over the basbousa, and allow to cool completely (preferably overnight before serving).